This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 3 |
| 2 | 12 |
| 3 | 53 |
| 4 | 246 |
| 5 | 1178 |
| 6 | 5768 |
| 7 | 28731 |
| 8 | 145108 |
| 9 | 741392 |
| 10 | 3825418 |
| 11 | 19907156 |
| 12 | 104370554 |
| 13 | 550816506 |
| 14 | 2924018194 |
| 15 | 15603778253 |
| 16 | 83661779470 |
| 17 | 450479003038 |
| 18 | 2435009205992 |
| 19 | 13208558795146 |
| 20 | 71879906857596 |
| 21 | 392320357251928 |
| 22 | 2147102400154768 |
| 23 | 11780181236675858 |
| 24 | 64782405317073968 |
| 25 | 357022158144941548 |